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Dynamic Modelling and Hybrid Non-Linear Model Predictive Control of Induced Draft Cooling Towers With Parallel Heat Exchangers, Pumps and Cooling Water Network

Thesis (PhD)--University of Pretoria, 2019.

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Other Authors: Craig, Ian K.
Format: Thesis
Language:English
Published: University of Pretoria 2019
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access_status_str Open Access
author2 Craig, Ian K.
author_browse Craig, Ian K.
author_facet Craig, Ian K.
collection Thesis
dc_rights_str_mv © 2019 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.
description Thesis (PhD)--University of Pretoria, 2019.
format Thesis
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institution University of Pretoria (South Africa)
language English
last_indexed 2026-06-10T12:39:24.464Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository
publishDate 2019
publishDateRange 2019
publishDateSort 2019
publisher University of Pretoria
publisherStr University of Pretoria
record_format dspace
source_str UPSpace — University of Pretoria Institutional Repository
spelling oai:repository.up.ac.za:2263/72415 Dynamic Modelling and Hybrid Non-Linear Model Predictive Control of Induced Draft Cooling Towers With Parallel Heat Exchangers, Pumps and Cooling Water Network Craig, Ian K. henning@swissmail.org Muller, Cornelius Jacobus Viljoen, Johannes Henning Dynamic modelling Cooling water network Optimisation Non-linear model predictive control Electricity consumption minimisation Cooling tower Particle swarm optimisation Hybrid systems Gradient descent UCTD Thesis (PhD)--University of Pretoria, 2019. In the process industries, cooling capacity is an important enabler for the facility to manufacture on specification product. The cooling water network is an important part of the over-all cooling system of the facility. In this research a cooling water circuit consisting of 3 cooling towers in parallel, 2 cooling water pumps in parallel, and 11 heat exchangers in parallel, is modelled. The model developed is based on first principles and captures the dynamic, non-linear, interactive nature of the plant. The modelled plant is further complicated by continuous, as well as discrete process variables, giving the model a hybrid nature. Energy consumption is included in the model as it is a very important parameter for plant operation. The model is fitted to real industry data by using a particle swarm optimisation approach. The model is suitable to be used for optimisation and control purposes. Cooling water networks are often not instrumented and actuated, nor controlled or optimised. Significant process benefits can be achieved by better process end-user temperature control, and direct monetary benefits can be obtained from electric power minimisation. A Hybrid Non-Linear Model Predictive Control strategy is developed for these control objectives, and simulated on the developed first principles dynamic model. Continuous and hybrid control cases are developed, and tested on process scenarios that reflect conditions seen in a real plant. Various alternative techniques are evaluated in order to solve the Hybrid Non-Linear Control problem. Gradient descent with momentum is chosen and configured to be used to solve the continuous control problem. For the discrete control problem a graph traversal algorithm is developed and joined to the continuous control algorithm to form a Hybrid Non-Linear Model Predictive controller. The potential monetary benefits that can be obtained by the plant owner through implementing the designed control strategy, are estimated. A powerful computation platform is designed for the plant model and controller simulations. Electrical, Electronic and Computer Engineering PhD Unrestricted 2019-11-28T07:13:58Z 2019-11-28T07:13:58Z 2020-04 2019 Thesis Viljoen, JH 2019, Dynamic Modelling and Hybrid Non-Linear Model Predictive Control of Induced Draft Cooling Towers With Parallel Heat Exchangers, Pumps and Cooling Water Network, PhD Thesis, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/72415> A2020 http://hdl.handle.net/2263/72415 en © 2019 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria
spellingShingle Dynamic modelling
Cooling water network
Optimisation
Non-linear model predictive control
Electricity consumption minimisation
Cooling tower
Particle swarm optimisation
Hybrid systems
Gradient descent
UCTD
Dynamic Modelling and Hybrid Non-Linear Model Predictive Control of Induced Draft Cooling Towers With Parallel Heat Exchangers, Pumps and Cooling Water Network
title Dynamic Modelling and Hybrid Non-Linear Model Predictive Control of Induced Draft Cooling Towers With Parallel Heat Exchangers, Pumps and Cooling Water Network
title_full Dynamic Modelling and Hybrid Non-Linear Model Predictive Control of Induced Draft Cooling Towers With Parallel Heat Exchangers, Pumps and Cooling Water Network
title_fullStr Dynamic Modelling and Hybrid Non-Linear Model Predictive Control of Induced Draft Cooling Towers With Parallel Heat Exchangers, Pumps and Cooling Water Network
title_full_unstemmed Dynamic Modelling and Hybrid Non-Linear Model Predictive Control of Induced Draft Cooling Towers With Parallel Heat Exchangers, Pumps and Cooling Water Network
title_short Dynamic Modelling and Hybrid Non-Linear Model Predictive Control of Induced Draft Cooling Towers With Parallel Heat Exchangers, Pumps and Cooling Water Network
title_sort dynamic modelling and hybrid non linear model predictive control of induced draft cooling towers with parallel heat exchangers pumps and cooling water network
topic Dynamic modelling
Cooling water network
Optimisation
Non-linear model predictive control
Electricity consumption minimisation
Cooling tower
Particle swarm optimisation
Hybrid systems
Gradient descent
UCTD
url http://hdl.handle.net/2263/72415